Protestants love to have Catholics explain the meaning of John 5:24 because they think it is an iron-clad proof text to support the Protestant doctrine of "Faith Alone." However, the Bible does not teach "Faith Alone" and "proof-texts" do not prove anything. They are usually ripped out of the context and twisted to fit whatever the person believes. This is not the way Scripture is to be read. When reading the Bible, we must pay close attention to content and unity. This means context is the key! No one verse is going to explain everything. So when we read Jn 5:24, we see that it says:
“Truly, truly, I say to you, he who hears my word and believes him who sent me, has eternal life; he does not come into judgment, but has passed from death to life."
So we have an affirmation that those who hear Christ's word and believe in God will have eternal life. Amen! We as Catholics believe that 100%. Yet what this verse does not say (and what Protestants think it says) is that the "only" thing we have to do is to hear Christ and believe. That surely is part of it, but not the sole thing. If we continue reading, Christ adds more requirements to salvation:
"Do not marvel at this; for the hour is coming when all who are in the tombs will hear his voice and come forth, those who have done good, to the resurrection of life, and those who have done evil, to the resurrection of judgment" (Jn 5:28-29).
Christ explicitly says here that we will be judge based on whether we have done good or evil. So Christ is clearly not teaching salvation by "Faith Alone" in verse 24, because four verses later he adds that our actions are also determinate of our salvation. We must not only believe in God and Jesus Christ, but we must live good and holy lives as well in order to be saved. Good works cannot earn us our salvation, but a lack thereof can surely cost us our salvation!